Hip dysplasia, a condition in which the two parts of the hip joint are poorly connected, is a common cause of severe osteoarthritis – especially among females. It often occurs at birth, but can develop later in life too, sometimes without warning. Read on to learn the causes and symptoms of hip dysplasia and learn the best treatments...

The thigh bone’s connected to the hip bone – that’s what the song says.

But sometimes that connection doesn’t work so well, resulting in a hip joint that’s dislocated, partially dislocated or loose.

These conditions, known as hip dysplasia, are the most common cause of hip arthritis in women under age 50.

They account for as many as 10% of hip replacements in the U.S., says Charles T. Price, M.D., director of the International Hip Dysplasia Institute at the Arnold Palmer Hospital for Children in Orlando, Fla.

Doctors screen every baby for symptoms of hip dysplasia.

When it’s caught early, it can be treated with braces, casts and sometimes surgery.

But some forms of the condition can develop later in life.

They may cause little or no pain for years, but – if untreated – eventually lead to osteoarthritis, deterioration of the joint, and the eventual need for total hip replacement surgery.

Whether you’re concerned about your own hip health or your child’s, here are answers to the most important questions about this often silent condition.

What exactly is hip dysplasia? It’s a catch-all term that describes a variety of malformations of the hip joint.

Picture a cup-shaped socket (called acetabula), which holds the ball-shaped top (femoral head) of the thigh bone (femur).

When the tight fit between these two pieces is lost, the top of the femur is able to move within or outside the hip.

It can be loosened within the joint, able to move to easily in and out of the joint (subluxated) or totally out of the joint (dislocated).

“Hip dysplasia describes any abnormal relationship between the ball and the socket,” says Michael J. Goldberg, M.D., director of the Skeletal Health Program at Seattle Children’s Hospital.

When do symptoms of hip dysplasia occur? About 10 out of every 1,000 babies are born with loose hips, says Dr. Goldberg.

For many of these infants, the problem will resolve within several months. But about 1 in 1,000 babies will either be born with hip dysplasia or develop it in the first years of life.

“In a newborn, the socket isn’t in a cup shape yet,” Dr. Goldberg says. “It’s actually more of a flat plate. It begins to round up and turn into the shape of a bowl, then a cup, and eventually it wraps around the ball-shaped top of the femur. This process continues until we stop growing.”

It can also show up later in life, in the teen years or even adulthood.

“The forms of hip dysplasia that involve the growth of the socket are often quite subtle,” says Arabella I. Leet, M.D., associate professor in the Division of Pediatric Orthopedics at Johns Hopkins Hospital in Baltimore.

Although the hip may not sit well in the socket, she says, it’s not likely to move in and out noticeably either.

As a result, it can be years before an adult discovers any symptoms of hip dysplasia.

“It’s sometimes diagnosed incidentally, when a woman has pain playing sports or when it shows up on an X-ray,” Dr. Leet says. “Sometimes we don’t know until the woman develops arthritis.”

What are the risk factors? There’s a strong genetic link, according to the American Academy of Pediatrics. Children whose parents had healthy hips have a 6% risk.

But when one parent has had hip dysplasia, the risk increases to 12%. And for children who have both a parent and a sibling with the condition, the risk increases to 36%.

It’s also more common in girls than boys, due to a hormone called relaxin that’s released by women during the birth process.

Relaxin loosens the mother’s hips to make childbirth easier, but it also affects the babies – especially girls – causing hip instability that can lead to dysplasia, according to the American Academy of Pediatrics (AAP).

Either hip (or both hips) can be affected, but dysplasia is three times as common on the left side – possibly due to the positioning of most babies in the womb, the AAP says.

It’s also more common in breech babies (those delivered feet- or buttocks-first), because their position limits movement of the legs and hips during fetal development.

What are symptoms of hip dysplasia in adults? If you have ongoing hip pain, are walking with a limp, or hear a clicking or popping noise in your hip, it’s a good idea to get an X-ray, says Dr. Leet.

Other conditions can also cause these symptoms – including uneven hip height or leg length.

So try to find a doctor who specializes in hip treatment, is aware of subtle joint abnormalities and has a lot of experience reading the X-rays.

“Hip dysplasia causes a deep ache on the front surface of the hip joint,” Dr. Price says. “If you’re having pain in the groin or the front of the hip that persists or gets worse, you should have it checked out.”

Or, Dr. Price says, “pain in the side of the hip is more likely to be caused by trochanteric bursitis” (inflammation of the bursa, a fluid-filled sac in the hip).

If I do have symptoms of hip dysplasia, what’s the treatment? If you’re under 50, your doctor will probably recommend you have hip-preservation surgery.

Known as an osteotomy, it reshapes the hip socket so that it covers the ball of the joint.

For young adults, the most common surgery is periacetabular osteotomy.

It reshapes and deepens the socket, which is then held in place with screws (which are sometimes removed later).

“This is a well-studied procedure with good outcomes,” Dr. Price says. “Once you’re fully recovered, you can return to activities, including sports.”

It also stops the deterioration of the joint, so you’re less likely to need total hip replacement surgery later in life.

The downside is the recovery period: six weeks on crutches and up to three months before you can start intensive rehabilitation, Dr. Price says.

“If you truly have dysplasia, it’s best to have the surgery early,” Dr. Price says. “Because it’s a mechanical disorder, postponing it can cause more damage. The quicker it’s diagnosed and treated surgically, the better the long-term outcome.”

Sometimes the cartilage is already so damaged this surgery isn’t an option. If that’s the case – or if you’re over 50 – your doctor may suggest total hip replacement surgery, known as arthroplasty. The damaged cartilage and bone are removed and replaced with artificial parts.

Expect to spend 3-5 days in the hospital; full recovery can take anywhere from 3-6 months.

What about other treatments – such as exercise and physical therapy – to relieve symptoms of hip dysplasia?There are ways to relieve pain – but “they won’t prevent the need for surgery,” Dr. Price says.

The strain on the joint will continue, and it will eventually deteriorate further.

In the meantime, any of these techniques may relieve your arthritis pain, suggests Dr. Leet.

Consider using a cane (on the side opposite the sore hip) to support your body weight.

Try nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen or naproxen.

Get physical therapy to increase flexibility and strengthen the muscles that support the hip.

Sign up for a water exercise class. This is a great way to work out without putting any strain on your joints.

Lose weight. Every 10 pounds you lose takes about 25 pounds of pressure off your hip.

Since it has a genetic link, should I be especially watchful for symptoms of hip dysplasia in my child?All babies are examined for hip dysplasia at their regular pediatric visits for at least the first year of life.

Babies who have risk factors, such as a family history or a breech birth, are tested with an ultrasound.

What can I expect during the exam? “The baby lies on his or her back, and we hold the knee in our hands with our fingers along the side of the leg,” says Harold Lehmann, M.D., associate professor of pediatrics at Johns Hopkins School of Medicine in Baltimore. “We look at the leg and hip to see how far the knee can spread, and we try to see if the femur comes out of, or snaps into, the socket.”

The doctor also looks for “clunks” and “clicks” that indicate movement in the joint, and will check to see if the legs appear symmetrical.

In cases that develop later, the first sign will sometimes be a limp or waddle as the child begins to walk.

You can look for some of these signs at home, says Dr. Leet.

“Sometimes if you’re diapering your child, you may hear or feel a popping,” she says. “If you feel something moving in the leg, talk to your pediatrician about it.”

If the doctor suspects an abnormality, he’ll order an ultrasound. For children older than six months, he or she may recommend an X-ray.

If your baby does have symptoms of hip dysplasia, you’ll be referred to an orthopedic surgeon, preferably one with a specialty in pediatrics.

What’s the treatment for hip dysplasia in babies? That depends on when it’s caught, says Dr. Leet.

If it’s found in the first months of life, your baby will wear a Pavlik harness, which holds the hip in its proper position.

In 1-2 months her ligaments should tighten around the hip joint and eventually support it in place.

What if the harness doesn’t help?The next step is for the orthopedist to maneuver the hip back into position and then hold it in place with a spica cast for 6-12 weeks.

This cast “encompasses the leg, with a cut-out for diapering, and goes up to the chest,” Dr. Leet explains. “The babies don’t seem to be uncomfortable in it.”

The doctor will generally use an X-ray with dye to see what he’s doing as he manually moves the leg back into the socket.

He may be able to do a “closed reduction,” with no incision.

Sometimes, however, the hip needs to be tightened surgically. This is called an “open reduction,” and requires anesthesia and an overnight hospital stay.

After treatment, the doctor will follow your child until he or she stops growing – about age 13 for girls and 16 for boys.

Is there anything I can do to minimize the risk of my baby developing symptoms of hip dysplasia after birth?The best way is to let your baby’s legs stay in their natural position, Dr. Price says.

“Infant hips have a lot of cartilage, so they’re very pliable,” he says. “Their natural position is frog-like, and it’s healthier for the hips if they stay in that position for a while.”

Try to avoid tightly swaddling your baby with her legs in full extension, he says.

A research review of swaddling practices concluded that’s a risk factor for hip dysplasia, according to a 2008 article in the journal Pediatrics.

In Japan, a nationwide campaign to reduce the tight swaddling of hips and knees led to a five-fold reduction in the incidence of hip dysplasia.

“Swaddling is good, but there’s just as much benefit in swaddling the arms and trunk while leaving room for the legs to move,” Dr. Price says.

You can find a video of safe swaddling methods at the International Hip Dysplasia Institute’s website.

How Much Do You Know About the Types of Arthritis?About 46 million American adults – nearly one in five – suffer from some type of arthritis. It’s estimated that number will rise to 67 million by 2030. Do you or someone close to you have arthritis? Take this quiz to see how much you know about this disease.

The information contained on www.lifescript.com(the "Site") is provided for informational purposes only and is not meant to substitute for advice from your doctor or health-care professional. This information should not be used for diagnosing or treating a health problem or disease, or prescribing any medication. Always seek the advice of a qualified health-care professional regarding any medical condition. Information and statements provided by the site about dietary supplements have not been evaluated by the Food and Drug Administration and are not intended to diagnose, treat, cure, or prevent any disease. Lifescript does not recommend or endorse any specific tests, physicians, third-party products, procedures, opinions, or other information mentioned on the Site. Reliance on any information provided by Lifescript is solely at your own risk.